Effect of early-life gut mucosal compromise on disease progression in NOD mice

Disease expression in spontaneous nonobese diabetic (NOD) mice depends on environmental stimuli such as stress, diet, and gut microbiota composition. We evaluated a brief, early-life gut intervention in which pups were weaned to low-dose dextran sulfate sodium (DSS). We hypothesized that the mucus-reducing effect of this compound and subsequent increased host–bacterial contact would delay disease onset and decrease insulitis due to enhanced oral tolerance. However, disease incidence did not differ between groups, although median survival (time point when 50% of the mice are still alive) of the control group was 184 d compared with 205 d for DSS-treated mice. Mean age at disease onset (that is, blood glucose of at least 12 mmol/L) was 164 d for control mice and 159 d for DSS-treated mice. In addition, 62.5% of control mice reached a blood glucose of 12 mmol/L before 30 wk of age compared with 59% in DSS-treated mice, which had a significant transient increase in serum insulin in week 4. No changes were found in immune cells collected from spleen, pancreatic lymph nodes, and mesenteric lymph nodes. Although mice received a low dose of DSS, the subsequent reduction in the diversity of the microbiota during weeks 4 through 6 led to increased cecal length and weight and, in week 13, a tendency toward decreased colon length, with increased leakage of LPS to the blood. We conclude that mucus reduction and subsequent increased host–bacterial contact did not affect overall disease progression in NOD mice.